There are many communication systems in operation today (including selective call systems) that provides message, data, and voice information. The communication subscriber units, e.g., selective call devices, utilize sophisticated receiver/transmitter architectures and signaling formats that have been optimized to provide both high receiver sensitivities and excellent battery saving capabilities.
In many metropolitan areas, there are many independent selective call communication systems or service providers. The selective call devices are able to scan a plurality of frequencies and select a frequency from the plurality of frequencies to monitor. An optimized battery saving protocol, e.g., the FLEX.RTM. family signaling protocol, enables selective call devices to remain connected for longer period of time without adversely affecting the user's expectation of battery life of the selective call device.
Receiving information on more than one frequencies or channels has always been an issue for most selective call signaling networks or systems since a selective call device can only monitor or receive information on one frequency or channel at a time. As generally the case, the two or more frequencies are independent networks or service providers that eliminates any coordination or scheduling of message transmission between the networks. Therefore, the networks will not know which frequency the selective call device is "listening" to at any given time. This problem is not resolved by prioritizing one network over the other because the lower priority network still does not know when the selective call device is monitoring the higher priority network. Thus, increasing the probability of missed messages.
Thus, what is need is a method and apparatus that enables a selective call device to receive messages on more than one network without missing messages and without communication or costly data transfer between independent networks.